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1# This file is part of daf_butler. 

2# 

3# Developed for the LSST Data Management System. 

4# This product includes software developed by the LSST Project 

5# (http://www.lsst.org). 

6# See the COPYRIGHT file at the top-level directory of this distribution 

7# for details of code ownership. 

8# 

9# This program is free software: you can redistribute it and/or modify 

10# it under the terms of the GNU General Public License as published by 

11# the Free Software Foundation, either version 3 of the License, or 

12# (at your option) any later version. 

13# 

14# This program is distributed in the hope that it will be useful, 

15# but WITHOUT ANY WARRANTY; without even the implied warranty of 

16# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 

17# GNU General Public License for more details. 

18# 

19# You should have received a copy of the GNU General Public License 

20# along with this program. If not, see <http://www.gnu.org/licenses/>. 

21 

22from __future__ import annotations 

23 

24import os 

25import os.path 

26import shutil 

27import urllib.parse 

28import posixpath 

29import copy 

30import logging 

31import re 

32 

33__all__ = ('ButlerFileURI',) 

34 

35from typing import ( 

36 TYPE_CHECKING, 

37 cast, 

38 Iterator, 

39 List, 

40 Optional, 

41 Tuple, 

42 Union, 

43) 

44 

45from ..utils import safeMakeDir 

46from .utils import NoTransaction, os2posix, posix2os 

47from ._butlerUri import ButlerURI 

48 

49 

50if TYPE_CHECKING: 50 ↛ 51line 50 didn't jump to line 51, because the condition on line 50 was never true

51 from ..datastore import DatastoreTransaction 

52 

53 

54log = logging.getLogger(__name__) 

55 

56 

57class ButlerFileURI(ButlerURI): 

58 """URI for explicit ``file`` scheme.""" 

59 

60 transferModes = ("copy", "link", "symlink", "hardlink", "relsymlink", "auto", "move") 

61 transferDefault: str = "link" 

62 

63 # By definition refers to a local file 

64 isLocal = True 

65 

66 @property 

67 def ospath(self) -> str: 

68 """Path component of the URI localized to current OS. 

69 

70 Will unquote URI path since a formal URI must include the quoting. 

71 """ 

72 return urllib.parse.unquote(posix2os(self._uri.path)) 

73 

74 def exists(self) -> bool: 

75 """Indicate that the file exists.""" 

76 # Uses os.path.exists so if there is a soft link that points 

77 # to a file that no longer exists this will return False 

78 return os.path.exists(self.ospath) 

79 

80 def size(self) -> int: 

81 """Return the size of the file in bytes.""" 

82 if not os.path.isdir(self.ospath): 

83 stat = os.stat(self.ospath) 

84 sz = stat.st_size 

85 else: 

86 sz = 0 

87 return sz 

88 

89 def remove(self) -> None: 

90 """Remove the resource.""" 

91 os.remove(self.ospath) 

92 

93 def _as_local(self) -> Tuple[str, bool]: 

94 """Return the local path of the file. 

95 

96 This is an internal helper for ``as_local()``. 

97 

98 Returns 

99 ------- 

100 path : `str` 

101 The local path to this file. 

102 temporary : `bool` 

103 Always returns `False` (this is not a temporary file). 

104 """ 

105 return self.ospath, False 

106 

107 def relative_to(self, other: ButlerURI) -> Optional[str]: 

108 """Return the relative path from this URI to the other URI. 

109 

110 Parameters 

111 ---------- 

112 other : `ButlerURI` 

113 URI to use to calculate the relative path. Must be a parent 

114 of this URI. 

115 

116 Returns 

117 ------- 

118 subpath : `str` 

119 The sub path of this URI relative to the supplied other URI. 

120 Returns `None` if there is no parent child relationship. 

121 Scheme and netloc must match but for file URIs schemeless 

122 is also used. If this URI is a relative URI but the other is 

123 absolute, it is assumed to be in the parent completely unless it 

124 starts with ".." (in which case the path is combined and tested). 

125 If both URIs are relative, the relative paths are compared 

126 for commonality. 

127 

128 Notes 

129 ----- 

130 By definition a relative path will be relative to the enclosing 

131 absolute parent URI. It will be returned unchanged if it does not 

132 use a parent directory specification. 

133 """ 

134 # We know self is a file so check the other. Anything other than 

135 # file or schemeless means by definition these have no paths in common 

136 if other.scheme and other.scheme != "file": 

137 return None 

138 

139 # for case where both URIs are relative use the normal logic 

140 # where a/b/c.txt and a/b/ returns c.txt. 

141 if not self.isabs() and not other.isabs(): 

142 return super().relative_to(other) 

143 

144 # if we have a relative path convert it to absolute 

145 # relative to the supplied parent. This is solely to handle 

146 # the case where the relative path includes ".." but somehow 

147 # then goes back inside the directory of the parent 

148 if not self.isabs(): 

149 childUri = other.join(self.path) 

150 return childUri.relative_to(other) 

151 

152 # By this point if the schemes are identical we can use the 

153 # base class implementation. 

154 if self.scheme == other.scheme: 

155 return super().relative_to(other) 

156 

157 # if one is schemeless and the other is not the base implementation 

158 # will fail so we need to fix that -- they are both absolute so 

159 # forcing to file is fine. 

160 # Use a cast to convince mypy that other has to be a ButlerFileURI 

161 # in order to get to this part of the code. 

162 return self.abspath().relative_to(cast(ButlerFileURI, other).abspath()) 

163 

164 def read(self, size: int = -1) -> bytes: 

165 """Return the entire content of the file as bytes.""" 

166 with open(self.ospath, "rb") as fh: 

167 return fh.read(size) 

168 

169 def write(self, data: bytes, overwrite: bool = True) -> None: 

170 """Write the supplied data to the file.""" 

171 dir = os.path.dirname(self.ospath) 

172 if not os.path.exists(dir): 

173 safeMakeDir(dir) 

174 if overwrite: 

175 mode = "wb" 

176 else: 

177 mode = "xb" 

178 with open(self.ospath, mode) as f: 

179 f.write(data) 

180 

181 def mkdir(self) -> None: 

182 """Make the directory associated with this URI.""" 

183 if not os.path.exists(self.ospath): 

184 safeMakeDir(self.ospath) 

185 elif not os.path.isdir(self.ospath): 

186 raise FileExistsError(f"URI {self} exists but is not a directory!") 

187 

188 def isdir(self) -> bool: 

189 """Return whether this URI is a directory. 

190 

191 Returns 

192 ------- 

193 isdir : `bool` 

194 `True` if this URI is a directory or looks like a directory, 

195 else `False`. 

196 """ 

197 return self.dirLike or os.path.isdir(self.ospath) 

198 

199 def transfer_from(self, src: ButlerURI, transfer: str, 

200 overwrite: bool = False, 

201 transaction: Optional[Union[DatastoreTransaction, NoTransaction]] = None) -> None: 

202 """Transfer the current resource to a local file. 

203 

204 Parameters 

205 ---------- 

206 src : `ButlerURI` 

207 Source URI. 

208 transfer : `str` 

209 Mode to use for transferring the resource. Supports the following 

210 options: copy, link, symlink, hardlink, relsymlink. 

211 overwrite : `bool`, optional 

212 Allow an existing file to be overwritten. Defaults to `False`. 

213 transaction : `DatastoreTransaction`, optional 

214 If a transaction is provided, undo actions will be registered. 

215 """ 

216 # Fail early to prevent delays if remote resources are requested 

217 if transfer not in self.transferModes: 

218 raise ValueError(f"Transfer mode '{transfer}' not supported by URI scheme {self.scheme}") 

219 

220 log.debug(f"Transferring {src} [exists: {src.exists()}] -> " 

221 f"{self} [exists: {self.exists()}] (transfer={transfer})") 

222 

223 # We do not have to special case ButlerFileURI here because 

224 # as_local handles that. 

225 with src.as_local() as local_uri: 

226 is_temporary = local_uri.isTemporary 

227 local_src = local_uri.ospath 

228 

229 # Default transfer mode depends on whether we have a temporary 

230 # file or not. 

231 if transfer == "auto": 

232 transfer = self.transferDefault if not is_temporary else "copy" 

233 

234 if not os.path.exists(local_src): 

235 if is_temporary: 

236 msg = f"Local file {local_uri} downloaded from {src} has gone missing" 

237 else: 

238 msg = f"Source URI {src} does not exist" 

239 raise FileNotFoundError(msg) 

240 

241 # Follow soft links 

242 local_src = os.path.realpath(os.path.normpath(local_src)) 

243 

244 # All the modes involving linking use "link" somewhere 

245 if "link" in transfer and is_temporary: 

246 raise RuntimeError("Can not use local file system transfer mode" 

247 f" {transfer} for remote resource ({src})") 

248 

249 # For temporary files we can own them 

250 requested_transfer = transfer 

251 if is_temporary and transfer == "copy": 

252 transfer = "move" 

253 

254 # The output location should not exist 

255 dest_exists = self.exists() 

256 if not overwrite and dest_exists: 

257 raise FileExistsError(f"Destination path '{self}' already exists. Transfer " 

258 f"from {src} cannot be completed.") 

259 

260 # Make the path absolute (but don't follow links since that 

261 # would possibly cause us to end up in the wrong place if the 

262 # file existed already as a soft link) 

263 newFullPath = os.path.abspath(self.ospath) 

264 outputDir = os.path.dirname(newFullPath) 

265 if not os.path.isdir(outputDir): 

266 # Must create the directory -- this can not be rolled back 

267 # since another transfer running concurrently may 

268 # be relying on this existing. 

269 safeMakeDir(outputDir) 

270 

271 if transaction is None: 

272 # Use a no-op transaction to reduce code duplication 

273 transaction = NoTransaction() 

274 

275 # For links the OS doesn't let us overwrite so if something does 

276 # exist we have to remove it before we do the actual "transfer" 

277 # below 

278 if "link" in transfer and overwrite and dest_exists: 

279 try: 

280 self.remove() 

281 except Exception: 

282 # If this fails we ignore it since it's a problem 

283 # that will manifest immediately below with a more relevant 

284 # error message 

285 pass 

286 

287 if transfer == "move": 

288 with transaction.undoWith(f"move from {local_src}", shutil.move, newFullPath, local_src): 

289 shutil.move(local_src, newFullPath) 

290 elif transfer == "copy": 

291 with transaction.undoWith(f"copy from {local_src}", os.remove, newFullPath): 

292 shutil.copy(local_src, newFullPath) 

293 elif transfer == "link": 

294 # Try hard link and if that fails use a symlink 

295 with transaction.undoWith(f"link to {local_src}", os.remove, newFullPath): 

296 try: 

297 os.link(local_src, newFullPath) 

298 except OSError: 

299 # Read through existing symlinks 

300 os.symlink(local_src, newFullPath) 

301 elif transfer == "hardlink": 

302 with transaction.undoWith(f"hardlink to {local_src}", os.remove, newFullPath): 

303 os.link(local_src, newFullPath) 

304 elif transfer == "symlink": 

305 # Read through existing symlinks 

306 with transaction.undoWith(f"symlink to {local_src}", os.remove, newFullPath): 

307 os.symlink(local_src, newFullPath) 

308 elif transfer == "relsymlink": 

309 # This is a standard symlink but using a relative path 

310 # Need the directory name to give to relative root 

311 # A full file path confuses it into an extra ../ 

312 newFullPathRoot = os.path.dirname(newFullPath) 

313 relPath = os.path.relpath(local_src, newFullPathRoot) 

314 with transaction.undoWith(f"relsymlink to {local_src}", os.remove, newFullPath): 

315 os.symlink(relPath, newFullPath) 

316 else: 

317 raise NotImplementedError("Transfer type '{}' not supported.".format(transfer)) 

318 

319 # This was an explicit move requested from a remote resource 

320 # try to remove that remote resource. We check is_temporary because 

321 # the local file would have been moved by shutil.move already. 

322 if requested_transfer == "move" and is_temporary: 

323 # Transactions do not work here 

324 src.remove() 

325 

326 def walk(self, file_filter: Optional[Union[str, re.Pattern]] = None) -> Iterator[Union[List, 

327 Tuple[ButlerURI, 

328 List[str], 

329 List[str]]]]: 

330 """Walk the directory tree returning matching files and directories. 

331 

332 Parameters 

333 ---------- 

334 file_filter : `str` or `re.Pattern`, optional 

335 Regex to filter out files from the list before it is returned. 

336 

337 Yields 

338 ------ 

339 dirpath : `ButlerURI` 

340 Current directory being examined. 

341 dirnames : `list` of `str` 

342 Names of subdirectories within dirpath. 

343 filenames : `list` of `str` 

344 Names of all the files within dirpath. 

345 """ 

346 if not self.isdir(): 

347 raise ValueError("Can not walk a non-directory URI") 

348 

349 if isinstance(file_filter, str): 

350 file_filter = re.compile(file_filter) 

351 

352 for root, dirs, files in os.walk(self.ospath): 

353 # Filter by the regex 

354 if file_filter is not None: 

355 files = [f for f in files if file_filter.search(f)] 

356 yield type(self)(root, forceAbsolute=False, forceDirectory=True), dirs, files 

357 

358 @classmethod 

359 def _fixupPathUri(cls, parsed: urllib.parse.ParseResult, root: Optional[Union[str, ButlerURI]] = None, 

360 forceAbsolute: bool = False, 

361 forceDirectory: bool = False) -> Tuple[urllib.parse.ParseResult, bool]: 

362 """Fix up relative paths in URI instances. 

363 

364 Parameters 

365 ---------- 

366 parsed : `~urllib.parse.ParseResult` 

367 The result from parsing a URI using `urllib.parse`. 

368 root : `str` or `ButlerURI`, optional 

369 Path to use as root when converting relative to absolute. 

370 If `None`, it will be the current working directory. This 

371 is a local file system path, or a file URI. It is only used if 

372 a file-scheme is used incorrectly with a relative path. 

373 forceAbsolute : `bool`, ignored 

374 Has no effect for this subclass. ``file`` URIs are always 

375 absolute. 

376 forceDirectory : `bool`, optional 

377 If `True` forces the URI to end with a separator, otherwise given 

378 URI is interpreted as is. 

379 

380 Returns 

381 ------- 

382 modified : `~urllib.parse.ParseResult` 

383 Update result if a URI is being handled. 

384 dirLike : `bool` 

385 `True` if given parsed URI has a trailing separator or 

386 forceDirectory is True. Otherwise `False`. 

387 

388 Notes 

389 ----- 

390 Relative paths are explicitly not supported by RFC8089 but `urllib` 

391 does accept URIs of the form ``file:relative/path.ext``. They need 

392 to be turned into absolute paths before they can be used. This is 

393 always done regardless of the ``forceAbsolute`` parameter. 

394 """ 

395 # assume we are not dealing with a directory like URI 

396 dirLike = False 

397 

398 # file URI implies POSIX path separators so split as POSIX, 

399 # then join as os, and convert to abspath. Do not handle 

400 # home directories since "file" scheme is explicitly documented 

401 # to not do tilde expansion. 

402 sep = posixpath.sep 

403 

404 # For local file system we can explicitly check to see if this 

405 # really is a directory. The URI might point to a location that 

406 # does not exists yet but all that matters is if it is a directory 

407 # then we make sure use that fact. No need to do the check if 

408 # we are already being told. 

409 if not forceDirectory and posixpath.isdir(parsed.path): 

410 forceDirectory = True 

411 

412 # For an absolute path all we need to do is check if we need 

413 # to force the directory separator 

414 if posixpath.isabs(parsed.path): 

415 if forceDirectory: 

416 if not parsed.path.endswith(sep): 

417 parsed = parsed._replace(path=parsed.path+sep) 

418 dirLike = True 

419 return copy.copy(parsed), dirLike 

420 

421 # Relative path so must fix it to be compliant with the standard 

422 

423 # Replacement values for the URI 

424 replacements = {} 

425 

426 if root is None: 

427 root = os.path.abspath(os.path.curdir) 

428 elif isinstance(root, ButlerURI): 

429 if root.scheme and root.scheme != "file": 

430 raise RuntimeError(f"The override root must be a file URI not {root.scheme}") 

431 root = os.path.abspath(root.ospath) 

432 

433 replacements["path"] = posixpath.normpath(posixpath.join(os2posix(root), parsed.path)) 

434 

435 # normpath strips trailing "/" so put it back if necessary 

436 # Acknowledge that trailing separator exists. 

437 if forceDirectory or (parsed.path.endswith(sep) and not replacements["path"].endswith(sep)): 

438 replacements["path"] += sep 

439 dirLike = True 

440 

441 # ParseResult is a NamedTuple so _replace is standard API 

442 parsed = parsed._replace(**replacements) 

443 

444 if parsed.params or parsed.query: 

445 log.warning("Additional items unexpectedly encountered in file URI: %s", parsed.geturl()) 

446 

447 return parsed, dirLike